The present invention relates to a method for producing a semiconductor light-emitting device.
In order to form a high-luminance semiconductor light-emitting device, it is important to increase the light emission efficiency as well as to achieve the improvement of current injection into the light-emitting section and the effective takeout of light to the outside of the device. In order to improve the current injection into the light-emitting section, a current diffusion layer, an intermediate layer capable of increasing the operating voltage and so on are effective, and the current diffusion layer is also effective for the purpose of achieving effective takeout of light to the outside of the device.
FIG. 28 shows a sectional view of a semiconductor light-emitting device having a current diffusion layer and an intermediate layer (prior art reference of Japanese Patent Laid-Open Publication No. HEI 9-260724). Referring to FIG. 28, an n-type AlGaInP lower clad layer 212, an AlGaInP active layer 213 and a p-type AlGaInP upper clad layer 214 are laminated on an n-type GaAs substrate 211, and a p-type AlGaInP intermediate layer 215 and a p-type GaP current diffusion layer 216 are laminated on the above processed base. Further, a p-type electrode 217, an n-type electrode 218 are formed by vapor deposition, completing a semiconductor light-emitting device. The composition of the p-type AlGaInP intermediate layer 215 is selected so as to satisfy the condition that its lattice matching factor is intermediate between that of the p-type AlGaInP upper clad layer 214 and that of the p-type GaP current diffusion layer 216, the condition that its conduction band lower end is intermediate between the conduction band lower end of the upper clad layer and the conduction band lower end of the current diffusion layer and/or the condition that its valence band upper end thereof is intermediate between the valence band upper end of the upper clad layer and the valence band upper end of the current diffusion layer in an energy position prior to the formation of a junction for the lowering of a hetero barrier in the energy band profile.
In this semiconductor light-emitting device, a current can be injected into not only a portion just below the electrode but also the entire active layer due to the provision of the p-type GaP current diffusion layer 216. FIGS. 29A and 29B show a band profile of a portion extending from the upper clad layer to the current diffusion layer. As shown in FIG. 29B, due to the provision of the p-type AlGaInP intermediate layer 215, energy discontinuity can be divided and reduced as compared with the one that has no intermediate layer shown in FIG. 29A. Therefore, the hetero barrier generated at the interface between the p-type AlGaInP upper clad layer 214 and the p-type GaP current diffusion layer 216 can be lowered. Furthermore, as compared with the one that employs no intermediate layer shown in FIG. 30A, according to this semiconductor light-emitting device shown in FIG. 30B, the lattice mismatching is alleviated by selecting a composition of a lattice constant of 5.55 xc3x85 that is intermediate between the lattice constant of 5.65 xc3x85 of the p-type AlGaInP upper clad layer 214 and the lattice constant of 5.45 xc3x85 of the p-type GaP current diffusion layer 216. With this arrangement, interface state densities generated at the interface between the upper clad layer 214 and the current diffusion layer 216 can be reduced, allowing the reduction of warp of band profile caused by the interface state densities. Therefore, as shown in FIG. 30B, the energy barriers at the interface can be reduced. By virtue of the effect of reducing these energy barriers, the operating voltage can be sharply reduced.
In the aforementioned semiconductor light-emitting device, the lattice mismatching is alleviated by employing AlGaInP having a lattice constant of 5.65 xc3x85 for the upper clad layer 214, employing AlGaInP having a lattice constant of 5.55 xc3x85 for the intermediate layer 215 and employing GaP having a lattice constant of 5.45 xc3x85 for the current diffusion layer 216. In contrast to this, there is still existing a large lattice mismatching of a lattice matching factor xcex94a/a of about xe2x88x921.8% between the p-type AlGaInP upper clad layer 214 and the p-type AlGaInP intermediate layer 215 and between the p-type AlGaInP intermediate layer 215 and the p-type GaP current diffusion layer 216. If such a large lattice mismatching exists, then it is difficult to grow a layer having good crystallinity above the interface where the lattice mismatching occurs, and a great many crystal defects such as crosshatch and hillock occur. In the above semiconductor light-emitting device, a great many crystal defects occur in the p-type AlGaInP intermediate layer 215 and the p-type GaP current diffusion layer 216, and the current diffusion and light transmittance are degraded in the current diffusion layer. This consequently causes degradation in light takeout efficiency and degradation in current injection efficiency. Furthermore, if the lattice mismatching exists, then a great many interface state densities occur at the interface. In this semiconductor light-emitting device, a great many interface state densities occur at the interface above and below the intermediate layer. As shown in FIG. 30B, the band profile from the upper clad layer to the current diffusion layer is alleviated by the intermediate layer, whereas the band profile at the hetero interface is sharply warped by the interface state densities, as a consequence of which the operating voltage is still not sufficiently lowered.
The aforementioned bad influence consequently causes a reduction in light takeout efficiency, a reduction in injection efficiency and an increase in operating voltage, and this leads to degradation in luminance, an increase in operating voltage and so on of the semiconductor light-emitting device. Furthermore, the crystal defects caused by the lattice mismatching exert many bad influences on the morphology of the surface of the semiconductor light-emitting device as well as the bad influences of the degraded adhesion of the electrode formed on the current diffusion layer and the disengagement of the electrode, and this leads to a reduced productivity as a consequence of a reduction in yield of production.
Accordingly, the object of the present invention is to provide a method for producing a high-productivity high-luminance semiconductor light-emitting device capable of operating at a low voltage.
In order to achieve the aforementioned object, the present invention provides a method for producing a semiconductor light-emitting device having a light-emitting section comprised of at least a lower clad layer, an active layer and an upper clad layer which are formed on a compound semiconductor substrate and a layer grown on the upper clad layer of the light-emitting section, wherein
when growing the layer on the upper clad layer from a crystal interface where crystal composition on the upper clad layer of the light-emitting section changes in a lattice mismatching state in which the absolute value of a lattice matching factor xcex94a/a between fore and hind crystals of the crystal interface is not lower than 0.25%, a growth rate at least at a start time of growth is made to be not greater than 1.0 xcexcm/h.
According to the above method of the present invention, the crystallinity of the layer to be grown on an interface where the lattice mismatching exists can be improved by setting a growth rate of not greater than 1.0 xcexcm/h at least in the initial stage of growth when growing the layer from a crystal interface where the crystal composition changes and there is a lattice mismatching of a lattice matching factor xcex94a/a of which the absolute value is not smaller than 0.25% between the fore and hind crystals. As a result, the transmittance of light emitted from the light-emitting section is increased, and the diffusion of current injected from the electrode and the efficiency of injection are increased. The adhesion of the electrode formed on the layer grown from the crystal interface to the layer is increased, and this leads to an increased yield. Therefore, a high-luminance high-productivity semiconductor light-emitting device can be obtained.
In an embodiment of the present invention, the layer grown on the upper clad layer of the light-emitting section includes at least one of a current diffusion layer and a current stopping layer.
According to the above embodiment, the crystallinity of the current diffusion layer or the current stopping layer can be improved by setting the growth rate of not greater than 1.0 xcexcm/h at least in the growth start stage of the current diffusion layer or the current stopping layer when there is a lattice mismatching of a lattice matching factor xcex94a/a of which the absolute value is not smaller than 0.25% between the current diffusion layer or the current stopping layer and the layer grown below the above layer. This enables the improvement of current diffusion or current stopping efficiency. Therefore, the diffusion of the current injected from the upper electrode and the injection efficiency are increased, and the transmittance of light emitted from the light-emitting section is increased in the current diffusion layer or the current stopping layer. Furthermore, the adhesion of the upper electrode formed on the current diffusion layer or the current stopping layer is increased, improving the yield of production. Therefore, a high-luminance high-productivity light-emitting device can be obtained.
The present invention also provides a method for producing a semiconductor light-emitting device having a light-emitting section comprised of at least a lower clad layer, an active layer and an upper clad layer which are formed on a compound semiconductor substrate, an intermediate layer formed on the upper clad layer of the light-emitting section and a layer grown on the intermediate layer, the intermediate layer being made of a material selected so as to satisfy a condition that a conduction band lower end of the intermediate layer is intermediate between a conduction band lower end of the upper clad layer and a conduction band lower end of the layer grown on the intermediate layer or a condition that a valence band upper end of the intermediate layer is intermediate between a valence band upper end of the upper clad layer and a valence band upper end of the layer grown on the intermediate layer in an energy position prior to the formation of a junction, wherein
when growing the intermediate layer on the upper clad layer in a lattice mismatching state in which the absolute value of a lattice matching factor xcex94a/a is not lower than 0.25% with respect to the upper clad layer, a growth rate at least at a start time of growth is made to be not greater than 1.0 xcexcm/h.
According to the above method of the invention, there is formed on the upper clad layer the intermediate layer so as to satisfy the condition that the conduction band lower end of the layer is intermediate between the conduction band lower end of the upper clad layer and the conduction band lower end of the layer grown on the intermediate layer and/or the condition that the valence band upper end of the layer is intermediate between the valence band upper end of the upper clad layer and the valence band upper end of the layer grown on the intermediate layer in the energy position prior to the formation of the junction. By setting the growth rate of not greater than 1.0 xcexcm/h at least in the initial stage of growth when growing the intermediate layer in the case where a lattice mismatching of a lattice matching factor xcex94a/a of which the absolute value is not smaller than 0.25% exists between the upper clad layer and the intermediate layer, the interface state densities caused by the lattice mismatching at the interface between the upper clad layer and the intermediate layer can be reduced, by which the warp of the band profile at the interface between the upper clad layer and the intermediate layer can be suppressed, allowing the operating voltage of the semiconductor light-emitting device to be reduced. Furthermore, the crystallinity of the layer grown on the intermediate layer is improved, and this consequently improves the transmittance of light emitted from the light-emitting section as well as the diffusion and injection efficiency of the current injected from the upper electrode. The adhesion of the electrode provided on the layer grown on the intermediate layer to the layer is increased, improving the yield of production. Therefore, a high-luminance high-productivity light-emitting device capable of operating at a low voltage can be obtained.
The present invention also provides a method for producing a semiconductor light-emitting device having a light-emitting section comprised of at least a lower clad layer, an active layer and an upper clad layer which are formed on a compound semiconductor substrate, an intermediate layer formed on the upper clad layer of the light-emitting section and a layer grown on the intermediate layer, the intermediate layer being made of a material selected so as to satisfy a condition that a conduction band lower end of the intermediate layer is intermediate between a conduction band lower end of the upper clad layer and a conduction band lower end of the layer grown on the intermediate layer or a condition that a valence band upper end of the intermediate layer is intermediate between a valence band upper end of the upper clad layer and a valence band upper end of the layer grown on the intermediate layer in an energy position prior to the formation of a junction, wherein
when growing the layer on the intermediate layer in a lattice mismatching state in which the absolute value of a lattice matching factor xcex94a/a is not lower than 0.25% with respect to the intermediate layer, a growth rate at least at a start time of growth is made to be not greater than 1.0 xcexcm/h.
According to the above method of the invention, there is formed on the upper clad layer the intermediate layer so as to satisfy the condition that the conduction band lower end of the layer is intermediate between the conduction band lower end of the upper clad layer and the conduction band lower end of the layer grown on the intermediate layer and/or the condition that the valence band upper end of the layer is intermediate between the valence band upper end of the upper clad layer and the valence band upper end of the layer grown on the intermediate layer in the energy position prior to the formation of the junction. By setting the growth rate of not greater than 1.0 xcexcm/h at least in the initial stage of growth when growing the layer on the intermediate layer in the case where a lattice mismatching of a lattice matching factor xcex94a/a of which the absolute value is not smaller than 0.25% exists between the intermediate layer and the layer grown on the intermediate layer, the interface state densities caused by the lattice mismatching at the interface between the intermediate layer and the layer grown on the intermediate layer can be reduced. Therefore, the warp of the band profile at the interface between the intermediate layer and the layer grown on the intermediate layer can be suppressed, allowing the operating voltage of the semiconductor light-emitting device to be reduced. Furthermore, the crystallinity of the layer grown on the intermediate layer is improved, and this consequently improves the transmittance of light emitted from the light-emitting section as well as the diffusion and injection efficiency of the current injected from the upper electrode. The adhesion of the electrode provided on the layer grown on the intermediate layer to the layer is increased, improving the yield of production. Therefore, a high-luminance high-productivity light-emitting device capable of operating at a low voltage can be obtained.
The present invention also provides a method for producing a semiconductor light-emitting device having a light-emitting section comprised of at least a lower clad layer, an active layer and an upper clad layer which are formed on a compound semiconductor substrate, an intermediate layer formed on the upper clad layer of the light-emitting section and a layer grown on the intermediate layer, the intermediate layer being made of a material selected so as to satisfy a condition that a conduction band lower end of the intermediate layer is intermediate between a conduction band lower end of the upper clad layer and a conduction band lower end of the layer grown on the intermediate layer or a condition that a valence band upper end of the intermediate layer is intermediate between the valence band upper end of the upper clad layer and a valence band upper end of the layer grown on the intermediate layer is satisfied in an energy position prior to the formation of a junction, wherein
when growing the intermediate layer on the upper clad layer in a lattice mismatching state in which the absolute value of a lattice matching factor xcex94a/a is not lower than 0.25% with respect to the upper clad layer and when growing the layer on the intermediate layer in a lattice mismatching state in which the absolute value of the lattice matching factor xcex94a/a is not lower than 0.25% with respect to the intermediate layer, a growth rate at least at a start time of growth is made to be not greater than 1.0 xcexcm/h.
According to the above method of the invention, there is formed on the upper clad layer the intermediate layer so as to satisfy the condition that the conduction band lower end of the layer is intermediate between the conduction band lower end of the upper clad layer and the conduction band lower end of the layer grown on the intermediate layer and/or the condition that the valence band upper end of the layer is intermediate between the valence band upper end of the upper clad layer and the valence band upper end of the layer grown on the intermediate layer in the energy position prior to the formation of the junction. By setting the growth rate of not greater than 1.0 xcexcm/h at least in the initial stage of growth when growing the intermediate layer and the layer on the intermediate layer in the case where a lattice mismatching of a lattice matching factor xcex94a/a of which the absolute value is not smaller than 0.25% exists between the intermediate layer and the layer grown on the intermediate layer and a lattice mismatching of a lattice matching factor xcex94a/a of which the absolute value is not smaller than 0.25% exists between the upper clad layer and the intermediate layer, the interface state densities caused by both the lattice mismatching at the interface between the intermediate layer and the layer grown on the intermediate layer and the interface between the intermediate layer and the layer grown on the intermediate layer can be reduced. Therefore, the warp of the band profile at the interface between the intermediate layer and the layer grown on the intermediate layer and the interface between the intermediate layer and the layer grown on the intermediate layer can be suppressed, allowing the operating voltage of the semiconductor light-emitting device to be reduced. Furthermore, the crystallinity of the layer grown on the intermediate layer is improved, and this consequently improves the transmittance of light emitted from the light-emitting section as well as the diffusion and injection efficiency of the current injected from the upper electrode. The adhesion of the electrode provided on the layer grown on the intermediate layer to the layer is increased, improving the yield of production. Therefore, a high-luminance high-productivity light-emitting device capable of operating at a low voltage can be obtained.
The present invention also provides a method for producing a semiconductor light-emitting device having a light-emitting section comprised of at least a lower clad layer, an active layer and an upper clad layer which are formed on a compound semiconductor substrate, an intermediate layer formed on the upper clad layer of the light-emitting section and a layer grown on the intermediate layer, the intermediate layer having a lattice constant intermediate between a lattice constant of the upper clad layer and a lattice constant of the layer grown on the intermediate layer, wherein
when growing the intermediate layer on the upper clad layer in a lattice mismatching state in which the absolute value of a lattice matching factor xcex94a/a is not lower than 0.25% with respect to the upper clad layer, a growth rate at least at a start time of growth is made to be not greater than 1.0 xcexcm/h.
According to the above method of the invention, there is formed on the upper clad layer the intermediate layer having a lattice constant intermediate between the lattice constant of the upper clad layer and the lattice constant of the layer grown on the intermediate layer. By setting the growth rate of not greater than 1.0 xcexcm/h at least in the initial stage of growth when growing the intermediate layer on the upper clad layer in the case where a lattice mismatching of a lattice matching factor xcex94a/a of which the absolute value is not smaller than 0.25% exists between the upper clad layer and the intermediate layer, the interface state densities caused by the lattice mismatching at the interface between the upper clad layer and the intermediate layer can be reduced, by which the warp of the band profile at the interface between the upper clad layer and the intermediate layer can be suppressed, allowing the operating voltage of the semiconductor light-emitting device to be reduced. Furthermore, the crystallinity of the layer grown on the intermediate layer is improved, and this consequently improves the transmittance of light emitted from the light-emitting section as well as the diffusion and injection efficiency of the current injected from the upper electrode. The adhesion of the electrode provided on the layer grown on the intermediate layer to the layer is increased, improving the yield of production. Therefore, a high-luminance high-productivity light-emitting device capable of operating at a low voltage can be obtained.
The present invention also provides a method for producing a semiconductor light-emitting device having a light-emitting section comprised of at least a lower clad layer, an active layer and an upper clad layer which are formed on a compound semiconductor substrate, an intermediate layer formed on the upper clad layer of the light-emitting section and a layer grown on the intermediate layer, the intermediate layer having a lattice constant intermediate between a lattice constant of the upper clad layer and a lattice constant of the layer grown on the intermediate layer, wherein
when growing the layer on the intermediate layer in a lattice mismatching state in which the absolute value of a lattice matching factor xcex94a/a is not lower than 0.25% with respect to the intermediate layer, a growth rate at least at a start time of growth is made to be not greater than 1.0 xcexcm/h.
According to the above method of the invention, there is formed on the upper clad layer the intermediate layer having a lattice constant intermediate between the lattice constant of the upper clad layer and the lattice constant of the layer grown on the intermediate layer. By setting the growth rate of not greater than 1.0 xcexcm/h at least in the initial stage of growth when growing the layer on the intermediate layer in the case where a lattice mismatching of a lattice matching factor xcex94a/a of which the absolute value is not smaller than 0.25% exists between the intermediate layer and the layer grown on the intermediate layer, the interface state densities caused by the lattice mismatching at the interface between the intermediate layer and the layer grown on the intermediate layer can be reduced, by which the warp of the band profile at the interface between the intermediate layer and the layer grown on the intermediate layer can be suppressed, allowing the operating voltage of the semiconductor light-emitting device to be reduced. Furthermore, the crystallinity of the layer grown on the intermediate layer is improved, and this consequently improves the transmittance of light emitted from the light-emitting section as well as the diffusion and injection efficiency of the current injected from the upper electrode. The adhesion of the electrode provided on the layer grown on the intermediate layer to the layer is increased, improving the yield. Therefore, a high-luminance high-productivity light-emitting device capable of operating at a low voltage can be obtained.
The present invention also provides a method for producing a semiconductor light-emitting device having a light-emitting section comprised of at least a lower clad layer, an active layer and an upper clad layer which are formed on a compound semiconductor substrate, an intermediate layer formed on the upper clad layer of the light-emitting section and a layer grown on the intermediate layer, the intermediate layer having a lattice constant intermediate between a lattice constant of the upper clad layer and a lattice constant of the layer grown on the intermediate layer, wherein
when growing the intermediate layer on the upper clad layer in a lattice mismatching state in which the absolute value of a lattice matching factor xcex94a/a is not lower than 0.25% with respect to the upper clad layer and when growing the layer on the intermediate layer in a lattice mismatching state in which the absolute value of the lattice matching factor xcex94a/a is not lower than 0.25% with respect to the intermediate layer, a growth rate at least at a start time of growth is made to be not greater than 1.0 xcexcm/h.
According to the above method of the invention, there is formed on the upper clad layer the intermediate layer having a lattice constant intermediate between the lattice constant of the upper clad layer and the lattice constant of the layer grown on the intermediate layer. By setting the growth rate of not greater than 1.0 xcexcm/h at least in the initial stage of growth when growing the layer on the intermediate layer in the case where a lattice mismatching of a lattice matching factor xcex94a/a of which the absolute value is not smaller than 0.25% exists between the upper clad layer and the intermediate layer and growing the layer on the intermediate layer in the case where a lattice mismatching of a lattice matching factor xcex94a/a of which the absolute value is not smaller than 0.25% exists between the intermediate layer and the layer grown on the intermediate layer, the interface state densities caused by the lattice mismatching both at the interface between the intermediate layer and the layer grown on the intermediate layer and the interface between the intermediate layer and the layer grown on the intermediate layer can be reduced, by which the warp of the band profile at the interface between the intermediate layer and the layer grown on the intermediate layer and the interface between the intermediate layer and the upper clad layer can be suppressed, allowing the operating voltage of the semiconductor light-emitting device to be reduced. Furthermore, the crystallinity of the layer grown on the intermediate layer is improved, and this consequently improves the transmittance of light emitted from the light-emitting section as well as the diffusion and injection efficiency of the current injected from the upper electrode. The adhesion of the electrode provided on the layer grown on the intermediate layer to the layer is increased, improving the yield. Therefore, a high-luminance high-productivity light-emitting device capable of operating at a low voltage can be obtained.
In one embodiment of the invention, the layer grown on the intermediate layer includes at least one of a current diffusion layer and a current stopping layer.
According to the above embodiment, when forming the current diffusion layer or the current stopping layer on the intermediate layer, the crystallinity of the current diffusion layer or the current stopping layer can be improved. This improves the current diffusion and current stopping efficiency, improves the transmittance of light emitted from the light-emitting section in the current diffusion layer or the current stopping layer and improves the diffusion or injection efficiency of the current injected from the upper electrode. The adhesion of the upper electrode formed on the current diffusion layer or the current stopping layer to the layer is increased, improving the productivity. Therefore, a high-luminance high-productivity light-emitting device capable of operating at a low voltage can be obtained.
In one embodiment of the invention, the intermediate layer is comprised of two or more layers.
According to the above embodiment, even in the semiconductor light-emitting device in which the intermediate layer is constructed of two or more layers, the generation of interface state densities and the degradation of crystallinity caused by the lattice mismatching at the interface between the intermediate layer and the upper clad layer and the interface between the intermediate layer and the layer formed on the intermediate layer can be suppressed. Therefore, a high-luminance high-productivity light-emitting device capable of operating at a low voltage can be similarly obtained.
In one embodiment of the invention, when growing an (n+1)-th intermediate layer in a lattice mismatching state in which the absolute value of a lattice matching factor xcex94a/a is not lower than 0.25% with respect to an n-th grown intermediate layer of the intermediate layers, a growth rate at least at a start time of growth is made to be not greater than 1.0 xcexcm/h.
According to the above embodiment, by setting a growth rate of not greater than 1.0 xcexcm/h at least in the growth start stage when growing the (n+1)-th intermediate layer in the case where a lattice mismatching of a lattice matching factor xcex94a/a of which the absolute value is not lower than 0.25% exists between the n-th grown intermediate layer and the (n+1)-th intermediate layer, the generation of interface state densities and the degradation of crystallinity due to the lattice mismatching at the interface between the intermediate layers can be suppressed. Therefore, a high-luminance high-productivity light-emitting diode capable of operating at a low voltage can be obtained.
In one embodiment of the invention, at least one layer out of the layers of which the growth rate at the start time of growth is not greater than 1.0 xcexcm/h is made to have a growth rate of greater than 1 xcexcm/h except when starting the growth.
According to the above embodiment, by setting a growth rate greater than 1 xcexcm/h except when starting the growth for at least one layer out of the layers of which the growth rate in the growth start stage is set not greater than 1.0 xcexcm/h, the time necessary for the growth can be reduced, allowing the time necessary for producing the semiconductor light-emitting device to be reduced. Therefore, a less expensive semiconductor light-emitting device can be obtained.
In one embodiment of the invention, the lower clad layer, the active layer, the upper clad layer, the intermediate layer, the current diffusion layer and the current stopping layer are made of (AlxGa1xe2x88x92x)yIn1xe2x88x92yP (0xe2x89xa6xxe2x89xa61, 0xe2x89xa6yxe2x89xa61).
According to the above embodiment, by using (AlxGa1xe2x88x92x)yIn1xe2x88x92yP (0xe2x89xa6xxe2x89xa61, 0xe2x89xa6yxe2x89xa61) for the lower clad layer, the active layer, the upper clad layer, the intermediate layer, the current diffusion layer and the current stopping layer, a high-luminance high-productivity light-emitting device capable of operating at a low voltage can be obtained.
In one embodiment of the invention, the lower clad layer, the active layer and the upper clad layer are made of (AlxGa1xe2x88x92x)yIn1xe2x88x92yP (0xe2x89xa6xxe2x89xa61, 0xe2x89xa6yxe2x89xa61) and the current diffusion layer and the current stopping layer are made of GaP.
According to the above embodiment, by employing (AlxGa1xe2x88x92x)yIn1xe2x88x92yP (0xe2x89xa6xxe2x89xa61, 0xe2x89xa6yxe2x89xa61) for the lower clad layer, the active layer and the upper clad layer and employing GaP for the current diffusion layer and the current stopping layer, a high-luminance high-productivity light-emitting device capable of operating at a low voltage can be obtained.
In one embodiment of the invention, a growth temperature at the time of ending the growth of the upper clad layer and growth temperatures of the intermediate layer and the current diffusion layer are made higher than a growth temperature of the light-emitting section except for the growth temperature at the time of ending the growth of the upper clad layer.
According to the above embodiment, by making the growth temperature at the time of ending the growth of the upper clad layer and the growth temperatures of the intermediate layer and the current diffusion layer higher than the growth temperature of the light-emitting section except for the growth temperature at the time of ending the growth of the upper clad layer, the crystallinity of the layer grown from the interface where the lattice mismatching occurs can be improved. As a result, the transmittance of light emitted from the light-emitting section is improved, and the diffusion or injection efficiency of the current injected from the upper electrode is improved. The adhesion of the electrode provided on the layer grown from the interface where the lattice mismatching occurs to the layer is increased, improving the productivity. Therefore, a high-luminance high-productivity light-emitting device capable of operating at a low voltage can be obtained.
In one embodiment of the invention, the lower clad layer, the active layer, the upper clad layer, the intermediate layer, the current diffusion layer and the current stopping layer are grown by a metal-organic chemical vapor deposition method.
According to the above embodiment, by using the metal-organic chemical vapor deposition method for the growth of the lower clad layer, the active layer, the upper clad layer, the intermediate layer, the current diffusion layer and the current stopping layer, a high-luminance high-productivity light-emitting device capable of operating at a low voltage can be easily produced.